Astronomy Cast

By Fraser Cain & Dr. Pamela Gay

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Astronomy Cast offers you a fact based journey through the cosmos. Each week Fraser Cain (Universe Today) and Dr. Pamela Gay (SIUE / Slacker Astronomy) take on topics ranging from the nearby planets to ubiquitous dark matter.

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Ep. 383: Approaches to Absolute Zero

The coldest possible theoretical temperature is Absolute Zero, this is the point at which no further energy can be extracted from a system. How are physicists working to get as close as possible to this extreme cold?

In some of the most extreme objects in the Universe, white dwarfs and neutron stars, matter gets strange, transforming into a material that physicists call “degenerate matter”. Let’s learn what it is, how it forms.

When we finally make the jump to fully colonizing the Solar System, we're going to want to use asteroids as stepping stones. We can use them as way stations, research facilities, even as spacecraft to further explore the Solar System. Today we'll talk abo

Astronomers rely on the optics of their instruments, and there are some basic limits that you just can’t avoid. Whatever we look at is distorted by the optics, in fact, a basic property of light means that we’ll never get perfect optics. Here’s why

When he wasn’t puzzling the mystery of alien civilizations, Enrico Fermi was splitting atoms. He realized that when atoms were split, the neutrons released could go on and split other atoms, creating a chain reaction – and the most powerful weapons ev

Physicists knew the interior of the atom contained protons, neutrons and electrons, but they didn’t understand exactly how they were organized. It took Ernest Rutherford to uncover our modern understanding.

At the end of the 19th century, physicists were finally beginning to understand the nature of matter itself, including the discovery of electrons – tiny particles of negative charge that surround the nucleus. Here’s how J.J. Thompson separated the ele

Evolution explains how life adapts and evolves over eons. But how did life originate? Chemists Miller and Urey put the raw chemicals of life into a solution, applied an electric charge, and created amino acids – the building blocks of life.

With the discovery of water ice in so many locations in the Solar System, scientists are hopeful in the search for life on other worlds. Guest Morgan Rehnberg returns to Astronomy Cast to explain the best places we should be looking for life.

In the world of quantum mechanics, particles behave in discreet ways. One breakthrough experiment was the Stern-Gerlach Experiment, performed in 1922. They passed silver atoms through a magnetic field and watched how the spin of the atoms caused the parti

Antoine Henri Becquerel discovered radioactivity completely by accident when he exposed a chunk of uranium to a photographic plate. This opened up a whole new field of research to uncover the source of the mysterious energy.

At the turn of the 20th Century, Einstein’s theory of relativity stunned the physics world, but the experimental evidence needed to be found. And so, in 1919, another respected astronomer, Arthur Eddington, observed the deflection of stars by the gravit

One of the most amazing implications of Einstein's relativity is the fact that the inertial mass of an object depends on its velocity. That sounds like a difficult thing to test, but that's exactly what happened through a series of experiments performed b

Light is tricky stuff, and it took scientists hundreds of years to puzzle out what this stuff is. But they poked and prodded at it with many clever experiments to try to measure its speed, motion and interaction with the rest of the Universe. For example,

Ep. 368: Searching for the Aether Wind: the Michelson–Morley Experiment

Waves move through a medium, like water or air. So it seemed logical to search for a medium that light waves move through. The Michelson-Morley Experiment attempted to search for this medium, known as the “luminiferous aether”. The experiment gave a n

We've spent the last few weeks talking about different ways astronomers are searching for exoplanets. But now we reach the most exciting part of this story: actually imaging these planets directly. Today we're going to talk about the work NASA's Spitzer S

Almost all the planet hunting has been done from space. But there’s a new instrument installed on the European Southern Observatory’s 3.6 meter telescope called the High Accuracy Radial velocity Planet Searcher which has already turned up 130 planets.

The European Gaia spacecraft launched about a year ago with the ambitious goal of mapping one billion years in the Milky Way. That’s 1% of all the stars in our entire galaxy, which it will monitor about 70 times over its 5-year mission. If all goes well

Before NASA’s Kepler mission searched for exoplanets using the transit method, there was the European COROT mission, launched in 2006. It was sent to search for planets with short orbital periods and find solar oscillations in stars. It was an incredibl

Where on Earth did our water come from. Well, obviously not from Earth, of course, but from space. But did it come from comets, or did the water form naturally right here in the Solar System, and the Earth just scooped it up?

It hard to think of a more influential modern planetary scientist than Carolyn Porco, the leader of the imaging team for NASA’s Cassini mission exploring Saturn. But before Cassini, Porco was involved in Voyager missions, and she’ll be leading up the

Maria Zuber is one of the hardest working scientists in planetary science, being a part of six different space missions to explore the Solar System. Currently, she’s the lead investigator for NASA’s GRAIL mission.

Our focus on female astronomers continues with Sandra Faber, and Professor of Astronomy at UC Santa Cruz. Faber was part of the team that turned up the Great Attractor, a mysterious mass hidden by the disk of the Milky Way.

It’s time for another series. This time we’ll be talking about famous female astronomers. Starting with: Vera Rubin, who first identified the fact that galaxies rotate too quickly to hold themselves together, anticipating the discovery of dark matter.

Getting stuff into space is complicated and expensive. And what do you do when your fancy space gadget breaks. You print out a new one, of course, with your fancy space 3D printer. It turns out, space exploration is one of the best uses for this technolog

We were witness to a once in a million year event. A close approach of Comet Siding Spring to the Planet Mars. And fortunately, humanity had a fleet of spacecraft orbiting the Red Planet, ready to capture this monumental event in real time. What did we se

You think we’re the only place that experiences seasons? Well, think again. Anything with a tilt enjoys the changing seasons, and that includes one of the most dramatic places in the Solar System: Saturn, with its rings and collection of moons.

Where ever we find water on Earth we find life. And so, it makes sense to search throughout the Solar System to find water. Well, here’s the crazy thing. We’re finding water just about everywhere in the Solar System. This changes our whole concept of

Live from DragonCon 2014! Fraser and Pamela are joined by Les Johnson, Scott Edgington, Erin MacDonald, Roy Kilgard, and Fraser bombards all of these wonderful scientists with the hardest, most complicated questions he can come up with!

Astronomy Cast’s 2014/15 season begins! With Rosetta’s arrival at Comet 67/P, we’re about to see a comet up close and personal. What will it take to explore, exploit and enjoy the asteroids and comets hurtling around our Solar System. And how does s

SpaceShipOne is the spacecraft created by Scaled Composites to win the $10 million Ansari X-Prize in 2003. It was the first privately built spacecraft to reach 100 km in altitude, twice in two weeks, carrying the equivalent of 3 people. It’s the prototy

Before the Apollo Program, there was the Gemini Program, and before Gemini came the Mercury Program. 7 elite astronauts chosen from a pool of military test pilots. How did NASA choose these original 7 men?

Although NASA is spread across the entire US, the headquarters is based right in Washington, DC. And the headquarters building is known as Two Independence Square. This is where past and future space policy for the agency was developed.

Who knows what mysteries lurk at the military's Area 51 complex in Nevada? Conspiracy theorists and UFO chasers think it's a big alien coverup. But it's probably something more boring, like advanced military aircraft. Let's talk about what we know, and wh

Almost every historic American launch occurred at one place in Cape Canaveral: Launch Complex 39. Good old LC39 was build for the Apollo spacecraft, and then modified for the Space Shuttle program. And now it’s carrying on this tradition for upcoming Sp

There’s so much we know about Saturn’s beautiful rings, and yet, there’s so much we don’t know. Morgan Rehnberg, a PhD student at the University of Colorado, Boulder and works with the Cassini mission. Morgan joins Fraser to talk about Saturn’s

We always say that the Universe is trying to kill you, but we thought we’d really hammer the point home. Dr. Phil Plait from Bad Astronomy joins Fraser Cain for a very special episode of Astronomy Cast. Join us as we hammer out all the ways the Universe

Everything dies, including our technology. But when we've hurtled a few thousands pounds of robotic instrumentation to another planet, it gets a little difficult to shut it down and clean up. What do we do when a mission has reached the end of its useful

Pamela has a day job, remember? As an astronomer? Recently the 45th Lunar and Planetary Science Conference occurred in the The Woodlands, Texas. Pamela and guest astronomer Sondy Springmann will let us know about the big announcements made at this year's

When the United States helped defeat Germany at the end of World War II, they acquired the German rocket scientist Wernher von Braun. He had already developed the German V2 rocket program, and went on to design all the major hardware of the US rocket prog

Yes, we actually landed on the Moon. No, aliens didn’t crash land at Roswell. What is it about space exploration that leads to so many conspiracy theories? We’ll try to get to the bottom of these conspiracy theories, poke holes in their ridiculous ide

It’s safe to say that the Polish astronomer Nicolaus Copernicus shook up the whole Universe. Well, our understanding of our place in the Universe. It was Copernicus who came up with the heliocentric model, placing the Sun at the center of the Solar Syst

There's a lot you can learn by just staring at an object, watching how it changes in brightness. This is the technique of photometry, and it has helped astronomers discover variable stars, extrasolar planets, minor planets, supernovae, and much more.

How heavy is a kilogram, how long is a second? How warm is a degree? We measure our Universe is so many different ways, using different units of measurement. But how do scientists come up with measurement tools which are purely objective?

Pop quiz. How did Einstein win his Nobel prize? Was it for relativity? Nope, Einstein won the Nobel Prize in 1921 for the discovery of the photoelectric effect; how electrons are emitted from atoms when they absorb photons of light. But what is it? Let’

Around this time last year a space rock crashed into the Earth above Chelyabinsk, Russia. It brightened the skies for hundreds of kilometers, broke windows and injured many people. Let’s look back at the event. What happened, and what did we learn?

Just take a look at the surface of the Moon and you can see it experienced a savage beating in the past. Turns out, the whole Solar System is a cosmic shooting gallery, with stuff crashing into other stuff. It sure sounds violent, but then, we wouldn't be

Out here in the Milky Way’s suburbs, stellar collisions are unheard of. But there are places in the galaxy where stars whiz past each other, and collisions can happen. When stars collide, it’s a catastrophic event, and the stellar wreckage is visible

In our previous episode, we introduced Arthur C. Clarke, the amazing man and science fiction writer. Today we’ll be discussing his legacy and ideas on space exploration. You’ll be amazed to hear how many of the ideas we take for granted were invented

Arthur C. Clarke was one of the greatest science fiction writers of all time. He defined the genre, and revolutionized our ideas about what it will take to become a true space faring civilization. In the first of our two part series on Arthur C. Clarke, w

As we’ve said before, all telescopes really want to be in space. In part 3 of our series on amateur telescope making, we bring you up to speed on the final frontier: amateurs building space telescopes. The hardware and software is available off the shel

Some astronomers are control freaks. It’s not enough to buy a telescope, they want to craft every part of the experience with their own hands. If you’re ready, and willing to get your hands dirty (and covered in glass dust), you can join thousands of

Why pick up a low quality, wobbly telescope from the department store when you can craft your own - just like Galileo, and all the great astronomers from history. For a minor investment, you can build a worthy telescope out of spare parts and high quality

When you consider the hazards of spaceflight, it’s hard to get worked up about dust bunnies. And yet, atmospheric dust is going to be one of the biggest problems astronauts will face when they reach the surface of other worlds. Where does this dust come

The Universe is filled with hot fusion, in the cores of stars. And scientists have even been able to replicate this stellar process in expensive experiments. But wouldn’t it be amazing if you could produce energy from fusion without all that equipment,

Comets can spend billions of years out in the Oort Cloud, and then a few brief moments of terror orbiting the Sun. These are the sun grazers. Some survive their journey, and flare up to become the brightest comets in history. Others won't survive their fi

The number of protons defines an element, but the number of neutrons can vary. We call these different flavors of an element isotopes, and use these isotopes to solve some challenging mysteries in physics and astronomy. Some isotopes occur naturally, and

As we’ve mentioned before, the Sun is a terrifying ball of plasma. It’s a good thing we’re keeping an eye on it. And that eye is the Solar and Heliospheric Observatory, or SOHO. Operating for more than 18 years now, SOHO has been making detailed obs

Sometimes the Sun is quiet, and other times the Sun gets downright unruly. During the peak of its 11-year cycle, the surface of the Sun is littered with darker sunspots. And its from these sunspots that the Sun generates massive solar flares, which can sp

Our Sun isn’t just a terrifying ball of white hot plasma, it’s actually a lot more complex. It’s got layers. And today, we’re going to peel back those layers and learn about the Sun – from the inside out.

Although the Zodiac is best known for astrology nonsense, it has a purpose in astronomy too. The constellations of the Zodiac define the plane of the ecliptic: the region where the Sun, Moon and planets appear to travel through the sky. What are the const

Sometimes you’ve just got to get away from it all. From your planet, your Solar System and your galaxy. If you’re looking to escape, you’ll need to know just what velocity it’ll take to break the surly bonds of gravity and punch the sky.

Have you ever wondered what it’s like to visit one of the big research observatories, like Keck, Gemini, or the European Southern Observatory? What’s it like to use gear that powerful? What’s the facility like? What precautions do you need to take w

Sometimes you can do science by watching patiently, and sometimes you've just got to get your hands dirty with an experiment or two. These two methods have their advantages and disadvantages for revealing Nature's secrets. Let's talk about how and why sci

Who knew that destruction could be so informative? Only by smashing particles together with more and more energy, can we truly tease out the fundamental forces of nature. Join us to discover the different kinds of accelerators (both natural and artificial

Put that pedal to the metal and accelerate! It's not just velocity, but a change in velocity. Let's take a look at acceleration, how you measure it, and how Einstein changed our understanding of this exciting activity.

The Earth is wobbling on its axis like a top. You can't feel it, but it's happening. And over long periods of time, these wobbles shift our calendars around, move the stars from where they're supposed to be, and maybe even mess with our climate. Thank you

Why don’t we have insects the size of horses? Why do bubbles form spheres? Why does it take so much energy to broadcast to every star? Let’s take a look at some non-linear mathematical relationships and see how they impact your day-to-day life.

Our modern society depends on science. It impacts the way we eat, work, communicate and play. And yet, most people take our amazing scientific advancement for granted, and some are even hostile to it. What can we do to spread the love of science through e

When it comes to carbon dioxide, just a little goes a long way to warming the planet. Unfortunately, we’ve been dumping vast amounts into the atmosphere, recently passing 400 parts per million. Let’s look at the science of the greenhouse effect, and h

The Pacific Ring of Fire wraps around the Pacific Ocean, including countries like Japan, Canada, New Zealand and Chile. And the inhabitants within those countries are prone to… oh… killer earthquakes, volcanoes and tsunamis. Let’s chat about the his

When too much material tries to come together, everything starts to spin and flatten out. You get an accretion disc. Astronomers find them around newly forming stars, supermassive black holes and many other places in the Universe. Today we’ll talk about

Last week we explored the various ways spacecraft can die. But this week, we explore the spacecraft (and the scientists) who never give up, snatching victory from the jaws of defeat. We’ll look at clever solutions to potential spacecraft catastrophes.

In the end, everything dies, even plucky space robots. Today we examine the last days of a series of missions. How do spacecraft tend to die, and what did in such heroes as Kepler, Spirit, and Galileo (the missions... not the people).

So many of the forces in space depend on equilibrium, that point where forces perfectly balance out. It defines the shape of stars, the orbits of planets, even the forces at the cores of galaxies. Let's take a look at how parts of the Universe are in per

Even the ancient astronomers knew there was something different about the planets. Unlike the rest of the stars, the planets move across the sky, backwards and forwards, round and round. It wasn’t until Copernicus that we finally had a modern notion of

We're so familiar with the current configuration of the planets in the Solar System, but did the planets always orbit in this way? Did they form further out and then migrate inward to their current positions? And what about other star systems out there?

We created Astronomy Cast to be timeless, a listening experience that's as educational in the future as it was when we started recording. But obviously, things have changed in almost 7 years and 300 episodes. Today we'll give you an update on some of the

Sometimes a trilogy needs four parts. We've looked at the history and modern era of space stations but now it's time to peer into the future at some space station concepts still in the works. Most of these will never fly, but the ideas are important. We

And now we reach the third part in our trilogy on space stations, with the largest vehicle ever assembled in space: the International Space Station. Launched in 1998, it now consists of 450 metric tonnes of modules, power systems and spacecraft and is re

Last week we introduced the history of space stations and focused on the US and Soviet stations that were launched. This week we look at one of the longest running missions ever launched: Mir. From its launch and construction to its fiery finale, Mir hel

It’s one thing to fly into space, and another thing entirely to live in space. And to understand the stresses and strains this puts on a human body, you’re going to need a space station. In this three-part series, we explore the past, present and fut

We understand our place in the Universe because of our direct observations. We can see the light that traveled billions of light years across space to reach us. This sphere of space is the observable universe; everything we can detect. But it’s really

We always say that the Universe is trying to kill you, but actually, the Earth isn't so fond of you either. Certain parts of planet Earth are prone to earthquakes, where the planet's shifting plates can cause the ground to shake violently. We've had a few

The mighty Arecibo Radio Observatory is one of the most powerful radio telescopes ever built – it’s certainly the larger single aperture radio telescope on Earth, nestled into a natural sinkhole in Puerto Rico. We’re celebrating the 50th anniversary

The very outer reaches of the Solar System is a region of space known as the Oort Cloud, which may extend as far as a light-year from the Sun. We only know about the Oort Cloud because that's where long-period comets come from, randomly falling into the i

As a meteor crashed into the atmosphere above Russia, the world discovered the importance of shock waves; how they're caused and how they propagate through the atmosphere. Today we'll discuss the topic in general and find many examples where shock waves c

If you get enough hydrogen together in one place, gravity pulls it together to the point that the temperature and pressures are enough for fusion to occur. This is a star. But what happens when you don't have quite enough hydrogen? Then you get a failed s

Sure, our atmosphere protects us from a horrible Universe that's trying to kill us, but sometimes it prevents us from learning stuff too. Case in point, the atmosphere blocks highly energetic particles from reaching our detectors. But there's a way astron

As we quickly learn with water, matter can be in distinct phases: solid, liquid, gas and plasma; it all depends on temperature. But why do different materials require different temperatures? And what's actually happening to the atoms themselves as the mat

It’s mind bending to think about this, but the light in your house, and the house itself are really the same thing. Matter and energy are interchangeable. This was the amazing revelation made by Albert Einstein, with his famous formula: E=mc^2. This is

Everyone is always predicting the end of the world. Someone’s going to tell you that this the year that it’s all going to end… the end of planet Earth… and they’re always wrong. But, someone will eventually be right. Planet Earth is doomed, let

Have you checked out the internet lately? Apparently there is some kind of rogue planet causing pole alignment and a killer solar flare that will set off a chain reaction turning the whole universe into strange-matter……. after an alien invasion.

Our Universe appears timeless and unchanging, the stars taking their nightly flight across the sky. But over long periods of time, you realize that our local region, and even the entire Milky Way is in constant motion. The constellations we see today wou

Spring, Summer, Autumn and Winter. These are the seasons we experience here on Earth as our planet completes an orbit around the Sun. But what’s going on? Why do we experience such different temperatures and weather over the course of 365 days? Do othe

We've all seen the classic science fiction space explosions, full of flames and loud sounds. Beautiful on the screen but, totally lacking in any kind of... science. What's wrong with science fiction? What would chemical and nuclear explosions really look

In order to allow for a static Universe, Albert Einstein introduced the concept of the Cosmological Constant Lambda to make the math work out. Once it was discovered that the Universe was actually expanding, he threw the number out calling it his "biggest

When Edwin Hubble observed that distant galaxies are speeding away from us in all directions, he discovered the reality that we live in an expanding Universe. Hubble worked to calculate exactly how fast this expansion is happening, creating the Hubble con

We always think about humans in space, but the cold hard reality is that animals have always been first in space. First to fly, first to orbit, and sadly, first to die. Let’s learn about how our animal companions have been our trusty partners in space e

When an object is orbiting the Earth, it’s really falling. The trick, described in the Hitchhiker’s Guide to the Galaxy, is how to throw yourself at the ground and miss. There are several different kinds of orbits, and they are good for different reas

The Earth’s atmosphere keeps us alive and blocks x-ray radiation from reaching the surface. In order to understand the universe at the higher energy levels you need to launch a space telescope like the European Space Agency’s XMM-Newton Telescope. Let

Isaac Newton has been called "the greatest and most influential scientist who ever lived." That sounds about right. He unlocked our modern understanding of gravity and laws of motion, dabbled in optics, philosophy... even alchemy. He was also known to hav

There’s some topics on Astronomy Cast that we wait until we are good and ready, until the science is all in. The Dawn mission has completed it’s mapping operations at asteroid Vesta and it’s now moving on to Ceres. This gives us a great opportunity

In Episode 24 we presented the concept of the Fermi Paradox. In short: Where are all the aliens? Today we’re going to examine the theoretical solutions to this problem. Maybe they’re out there, but just don’t want to talk to us. Maybe it’s too har

The Theory of Evolution provides a rich explanation for why we see the diversity of life here on Earth. There are so many lines of evidence, from genetic drift to the fossil record. But how did life start? How did things go from a collection of raw materi

In past, if you looked up into the sky, you were an astronomer. But everything has gotten so complicated. Now we have astrophysicists, and cosmologists, planetary geologists, and even exobiologists. Who does what, and how do they all interact with one ano

We've probed the deepest recesses of the universe, landed spacecraft and humans on other planets and moons but face it all of this exploration is expensive. Just a single spacecraft can cost billions. Who pays for all this stuff?

An object at rest tends to stay at rest. An object in motion tends to stay in motion. Isaac Newton dismantled the traditional idea that objects would tend to slow down over time, and described the concept of inertia: the amount an object will resist chang

Last week we talked about energy, and this week we’ll talk about mass. And here’s the crazy thing. Mass, matter, the stuff that the Universe is made of, is the same thing as energy. They’re connected through Einstein’s famous formula – E=mc2. Bu

Our entire civilization depends on energy: getting it, converting it, burning it, and conserving it. But how do physicists think about energy? How do they measure and quantify it. And what is energy's special relationship with mass?

Forever is a funny thing. Today we’re going to talk about infinities. That’s right, all the different kinds of possible infinities. How you add them, subtract them, and use them to think about the scale of the Universe

It's time to look deep into history to the birthplace of modern mathematics - Ancient Greece. And the most famous mathematician of the time was Archimedes. We use many of his mathematical theories and inventions to this day; others are steeped in legend a

We can thank Arthur Eddington for much of our current understanding of stars. He provided some of the breakthrough concepts that explain what’s going on, deep inside the hottest places in the Universe. Sadly, the spacecraft associated with his name wasn

We hold all these romantic notions about humans exploring the Solar System, turning humanity into a true spacefaring race. But the cold hard reality is that space, really the entire Universe, is trying to kill you. Any humans venturing out into space will

Nothing lasts forever, even atoms. Heavier elements decay into lighter elements, releasing energy as radiation. But thanks to this radiation, astronomers can get a glimpse into what's going on inside distant start. Let's take a look at the whole process o

Wouldn’t it be cool to explore the cosmos, powered only by sunlight caught by your shimmering solar sail? It sounds like science fiction, but it’s serious science – a test sail has even been sent to orbit. It might even be a way to travel from star

Last week we introduced the science of lasers and masers. This week we apply that knowledge to our favourite field: astronomy. Learn how naturally forming masers teach us about the cosmos, and how the artificially produced lasers help us gather better sci

Just when you think you understand it, light will do some amazing things. Just look at the discovery of lasers, and their use in almost every technology you can think of: from cutting, to transmitting information to, yes, astronomy. And nature has figured

Mars gets all the attention, but you might be surprised to know how much Venus has been explored. From initial telescope observations and the early flyby missions, to the landers… yes landers and orbiters. We know quite a lot about Venus, but the planet

Last week we talked about the orbiter portion of the Viking Missions. But that was only half the adventure. Each Viking spacecraft carried a lander as well, which touched down on the surface of Mars, searching for evidence of past and current life. And wh

Spirit, Opportunity and Curiosity get all the news now, but it was NASA's Viking Missions that gave us our first close up view of the surface of Mars. These twin missions, both made of orbiter and lander set the stage for the exploration of Mars, demonstr

When it comes to telescopes, astronomers really just care about resolution: how much can you see? Your resolution defines how much science you can get done, and it depends on your gear, wavelength, and conditions. Putting a telescope in space really helps

Hydrogen is the most common element in the Universe, formed at the beginning of everything in the Big Bang. It's the raw material of stars, gathering together through mutual gravity into vast nebulae. Astronomers can learn so much looking for hydrogen in

Light can do some pretty strange stuff, like pass through objects and bounce off them; it can be broken up and recombined. In fact, everything we "see" is actually the end result of reflection and refraction of light. Time to understand how it all works.

Next time a kid asks you, why is the sky blue? Answer them: because of Rayleigh scattering. If they’re not happy with that answer, feel free to expand based on the knowledge we’re about to drop today, right into your brain.

Quantum theory is plenty strange, but one of the strangest discoveries is the realization that there’s a limit to how much you can measure at any one time. This was famously described by Werner Heisenberg, with his uncertainty principle: how you can nev

Have you ever looked into the sky and noticed a fuzzy blob? That’s a Messier Object, carefully cataloged by Charles Messier to make it easier to find comets. We’ll learn about the history of the catalog, Messier’s criteria and some of the prominent

Accuracy, precision and reproducibility. These are the foundations of science that make our progress possible. How do these play into a scientist’s daily activities? And just how precise can we get with our measurements?

You’ve probably all heard of Schrödinger’s Cat, that strange thought experiment designed by Erwin Schrödinger to show how the strange predictions of quantum theory could impact the real world. No cats will be harmed in the making of this episode, ma

Time for another detailed look at a constellation; one of the most fascinating in the sky, but hidden to most of the northern hemisphere: Carina. Home to one of the most likely supernova candidates we know of: Eta Carinae. Let’s talk just about this con

This is going to be one of the “how we know what we know” kind of shows. How do scientist determine the age of things? How do we know the age of everything from stone tools, to the age of the Earth, to the age of the very Universe.

The number of moons, the age of the Sun, and our placement in the Milky Way all had an impact on the formation of the Earth and the evolution of life on our planet. But what if things were different? What would be the implications?

Our lives are ruled by calendars. And calendars are ruled by astronomy. As we near the end of 2011, and get ready to ring in the new year, let’s discover the astronomy underlying the days, weeks, months and years that segment our lives.

If you want to see one of the strangest places in the Solar System, look no further than Io, Jupiter's inner Galilean moon. The immense tidal forces from Jupiter keep the moon hotter than hot, with huge volcanoes blasting lava hundreds of kilometres into

On June 30th, 1908 “something” exploded over the Tunguska region of Siberia, flattening thousands of square kilometres of forest, and unleashing a force that rivalled the most powerful nuclear weapon ever detonated. What was it? What could unleash tha

When you hear of a looming asteroid strike, do you wonder what to do? Should you go into your underground bunker, evacuate the state, or leave the planet? Fortunately, astronomers have developed the Torino Scale – a handy measurement that incorporates b

Time for part 3 of our tour through the hobby of astrophotography. You’ve set up your gear, taken some clear images. Now we’re going to help you turn that raw data into the kind of amazing photographs you see in books and on the web.

In the first episode, we talked about the gear you'll need for your expensive astrophotography hobby. This week we continue our discussion, and talk about the techniques you'll use to get those amazing photographs. Bring a hot drink, and get ready for som

No matter how good your telescope is, you're never going to see the same detail and colours as the photographs. To take amateur astronomy to the next level, you really need to attach a camera to your telescope. Welcome to the hobby of astrophotography. Fa

The Sun looks like a harmless burning ball of fire in the sky: warm, life-giving and forever unchanging. But we know better, don’t we. It’s really a massive ball of churning hydrogen plasma, encased in twisting magnetic field lines, speckled with suns

To help you out with your halloween parties, we’ve collected together the spooky sounds of space. Every piece of audio we’re about to play might sound like it comes from a terrifying nightmare dimension, but it’s really just a natural space phenomen

At least once a week we get an email claiming that Einstein was wrong. Well you know what, Einstein was right. In fact, as part of his theories of Special and General Relativity, Einstein made a series of predictions about what experiments should discover

What can we say about Einstein? Albert Einstein! Lots, actually. In this show we’re going to talk about the most revolutionary physicist… ever. He completely changed our understanding of time, and space, and energy, and gravity. He made predictions ab

This is an impromptu episode of Astronomy Cast that we recorded during Dragon*Con 2011. Pamela was scheduled to speak with a panel about strange things in space, but she ended up being the only person there. So Fraser jumped in, and this was what we did.

The Moon is a stark reminder that we actually live in a Universe filled with stars and planets and moons. The changing phases of the Moon show us the relative positions of the Earth, the Sun and the Moon as they interact with one another. Let's learn abou

Radar is one of the those technologies that changed everything: it allows boats and aircraft to “see” at night and through thick fog. But it also changed astronomy and ground imaging, tracking asteroids with great accuracy, allowing spacecraft to peer

In last season’s thrilling cliff hanger, we talked about astronomer superhero Galileo Galilei. Will a mission be named after him? The answer is yes! NASA’s Galileo spacecraft visited Jupiter in 1995, and spent almost 8 years orbiting, changing our und

It’s hard to imagine a more famous astronomer than Galileo Galilei. He’s widely recognized as the very first person to point a telescope at the skies and then study what he saw. Galileo discovered the moons of Jupiter, the phases of Venus, and much mo

And now we finish our trilogy of Saturnian astronomers and missions with a look at the Dutch astronomer and mathematician, Christiaan Huygens. It was Huygens who discovered Titan, and figured out what Saturn’s rings really are, so it makes sense that a

Last week we talked about the Italian astronomer Giovanni Cassini. This week we’ll talk about the mission that shares his name: NASA’s Cassini Spacecraft. This amazing mission is orbiting Saturn right now, sending back thousands of high resolution ima

Another two parter, coming at you. This week we talk about the Italian astronomer, Giovanni Domenico Cassini, best known for discovering Saturn's moons and the biggest division in Saturn's rings. Cassini made many other important discoveries in the Solar

We wanted to spend a few shows talking about some of the most recognizable constellations in the night sky. We've chatted about Orion the Hunter, but now we're going to talk about the Big Dipper, also known as Ursa Major, or the Great Bear - apologies to

How's the weather? Maybe a better question is... why's the weather? What is it about planets and their atmospheres that create weather systems. What have planetary scientists learned about our Earth's weather, and how does this relate to other planets in

A huge part of the Solar System is just made of ice. There are comets, rings, moons and even dwarf planets. Where did all this ice come from, and what impact (pardon the pun) has it had for life on Earth?

Most people know how to find two constellations: the Big Dipper, and Orion the Hunter. You can teach a small child to find Orion, and at the right time of year, they'll find it in seconds. There's so much going on in this spectacular constellation, from t

Since the planet Venus is closer in to the Sun than Earth, there are rare opportunities to see it pass directly in front of our parent star. This is known as a planetary transit, and thanks to the geometry of the Earth and Venus, they only happen a couple

In episode 198 we explained how space missions are chosen, and introduced the Decadal Survey. Since the time we recorded that episode, the full Decadal Survey for planetary science has been released, explaining the science goals for planetary geologists o

When we look around our planet, we see a huge variety in landforms: mountains, valleys, plateaus, and more. Continents rise and fall over the eons, providing geologists with a history of the planet's evolution. The study of these changes is known as geomo

The Earth seems like a safe place, most of the time. But we have evidence of terrible catastrophes in the ancient past. Times when almost all life on Earth was wiped out in a geologic instant. What could have caused so much devastation? And will something

Another mission named after a famous physicist. This time we're looking at the Planck mission, designed to study the Cosmic Microwave Backgorund Radiation over the entire sky. Like the previous WMAP mission, this will help astronomers understand the first

It's time for another action-packed double episode, where we meet a man and his mission. This time around its German physicist Max Planck, considered to be the father of quantum theory - he was later granted a Nobel Prize for just that discovery. Let's ta

Have you ever heard an astronomer utter these words? Oh be a fine girl and kiss me. They’re not being romantic, they’re trying to remember the different ways to organize stars, as detailed nicely on a Hertzsprung–Russell diagram. Let’s learn what

The Sun, Moon, stars and planets are visible to the unaided eye, and so they have been visible to astronomers since before recorded history. Some of the earliest records we do have tell us what the ancient astronomers thought about the heavens, and how th

Just as sound can echo off distant objects, light can echo too. And the echoes of light bouncing off stellar remnants, black hole accretion disks, and clouds of gas and dust provide astronomers with another method of probing the distant cosmos.

Have you ever wanted to go to space, but lacked the... everything... to be an astronaut? A whole new industry of space tourism will take you where you need to go. There are new companies offering zero-G flights, sub-orbital flights, and there have even be

It's now believed that there's a supermassive black hole lurking at the heart of every galaxy in the Universe. These monstrous black holes can contain hundreds of millions of times the mass of our own Sun, with event horizons better than the Solar System.

Before there was GPS, navigators had to rely on the Sun and the stars to find their way around the Earth. It's easier than it sounds, if you've got the right instruments, clear skies, and a really accurate clock. Let's examine the history of celestial nav

The twin Mars Exploration Rovers, Spirit and Opportunity, have been crawling around the surface of Mars since early 2004 – years longer than they were expected to live. And what they have discovered there on Mars has given scientists their best understa

We don’t like cover news on Astronomy Cast, but sometimes there’s a news story that’s interesting, complicated, and rapidly unfolding – and it happens to cover an area that we haven’t talked much about. So today we thought we’d talk about the

Last week we talked about Lyman Spitzer, and this week we’ll take a look at the orbiting observatory that bears his name: the Spitzer Space Telescope. Designed to see into the infrared spectrum, Spitzer has returned images of objects that were previousl

Time for another action-packed double episode of Astronomy Cast. This week we focus on the Lyman Spitzer, a theoretical physicist and astronomer who worked on star formation and plasma physics. Of course, this will lead us into next week’s episode where

Last week we talked about fusion, where atoms come together to form heavier elements. This week, everything comes apart as we talk about nuclear fission. How it occurs naturally in the Universe, and how it has been harnessed by science to produce power, a

When the Universe formed after the Big Bang, all we had was hydrogen. But through the process of fusion, these hydrogen atoms were crushed into heavier and heavier elements. Fusion gives us warmth and light from the Sun, destruction with fusion bombs, and

Now we're going to answer a question that a 4-year old might ask - what is temperature? Why are things hot and why are they cold? How hot or cold can they get? And how is this all important for astronomy?

Europa is the smallest of the Jovian satellites, but it might be one of the most exciting spots in the Solar System. When NASA’s Voyager spacecraft flew past the moon, they discovered huge cracks in its icy surface. Is it possible that Europa has a huge

With the discovery of a planet in the habitability zone of Gliese 581, the chances of finding life on other worlds is just getting better and better. Let’s take a look at the discoveries made at Gliese 581, provide some perspective on the real chances o

Titan is Saturn’s largest moon, and the second largest moon in the Solar System. It’s unique in the Solar System as the only moon with an atmosphere. In fact, scientists think that Titan’s thick atmosphere – rich in hydrocarbons – is similar to

The first interplanetary series of missions was the American Mariner program. These successful spacecraft visited Mercury, Venus, and Mars, and laid the groundwork for the US missions to the outer planets. Let's take a look at the program and their incred

Launched in 1977, the twin Voyager spacecraft were sent to explore the outer planets: Jupiter, Saturn, Uranus and Neptune. Because of a unique alignment of the planets, Voyager 2 was the first spacecraft to ever make a close approach to Uranus and Neptune

Space missions are expensive to build and launch, so there’s a lot of planning that goes into choosing exactly what’s going to be shot into space. Space scientists and engineers recently went through the process of deciding on their science goals, so

In this special live Dragon*Con 2010 episode of Astronomy Cast we welcomed special guest Les Johnson, Deputy Manager for NASA’s Advanced Concepts Office to talk about the state of human space exploration. And then we opened up the show to some amazing q

Astronomers measure the brightness of stars as magnitude. But this brightness depends on the distance to the star as well as the total amount of energy it's pumping out into space. And from our vantage point here on Earth, appearances can be deceiving.

Saturn is best known for its rings. This huge and beautiful ring system is easy to spot in even the smallest backyard telescope, so you can imagine they were a surprise when Galileo first noticed them. But astronomers have gone on to find rings around the

In 2006, the International Astronomical Union demoted Pluto out of the planet club. But they also started up a whole new dwarf planet club, with Pluto, Eris and the asteroid Ceres as charter members. Let’s find out what it takes to be a dwarf planet, an

We talk a lot about telescopes here on Astronomy Cast, but you really don't need any special equipment to appreciate what the night sky has to offer. Just head outside with some sky charts, maybe a planisphere, some friends and hot chocolate, and you're g

The Chandra X-Ray Observatory is the third of NASA's Great Observatories, sent into space aboard the space shuttle to view the Universe in high energy X-ray radiation. This is the territory of supernovae, supermassive black holes and neutron stars; some o

The first half of the 20th Century was a productive time for astronomy, with theorists working out much of the science that we take for granted today. One of these astronomy stars was Subrahmanyan Chandrasekhar, who determined the maximum mass of a white

Last week we studied Kepler the man, and this week we take a look at Kepler, the mission. Launched in March, 2009, this is a spacecraft designed to search for Earth-like planets orbiting other stars. Let's take a look at the history this mission, the laun

Nicolaus Copernicus changed our understanding of the Universe when he rearranged the Solar System to put the Sun at the center, with the Earth becoming just another of the planets orbiting it. But the movement of the planets didn't really match the theory

We spent 5 episodes telling the story of astronomy so far, how we got from the work of the Babylonians to the modern discoveries made in the last decade. But now we want to look forward, studying the current space missions and experiments to uncover the m

Ep. 186: History of Astronomy, Part 4: The Beginning of Modern Astronomy

With our proper place in the Universe worked out, and some powerful telescopes to probe the cosmos, astronomers started making some real progress. The next few hundred years was a time of constant refinement, with astronomers discovering new planets, new

Now we reach time with names that many of you will be familiar: Galileo, Kepler, Copernicus. This is an age when the biggest names in astronomy used the best tools of their time to completely rearrange their understanding of the Universe, putting the Eart

With the earliest astronomers out of the way, we now move to one of the most productive eras in astronomy; the ancient Greeks. Even though they didn't have telescopes, the Greeks worked out the size and shape of the Earth, the distance to the Moon and Sun

We know you love a good series. This time we're going to walk you through the history of astronomy, starting with the ancient astronomers and leading right up to the most recent discoveries. Today we're going to start at the beginning, with the astronomer

Astronomers have been cataloging star positions for thousands of years, from the first calculations made by Hipparchus, to the more recent star catalogs made by the spacecraft named after him. This is astrometry; another way to find our place in the Unive

Everything in the Universe is spinning. In fact, without this rotation, life on Earth wouldn't exist. We need the conservation of angular momentum to flatten out galaxies and solar systems, to make planets possible. Let's find out about the physics involv

Why are some objects in the Solar System bright while others are dim? Much of an object's brightness is caused by its albedo, or how well it reflects radiation from the Sun. If you want to know how big a distant moon, comet, or asteroid is, you've got to

Today we tackle more thrilling mysteries of the Universe. And by tackle, we mean, acknowledge their puzzling existence. Some mysteries will be solved shortly, others will likely trouble astronomers for centuries to come. Join us for part 2.

All finished with the Milky Way, it's time to move on to the biggest mysteries of all. The mysteries of the Universe. Let's wonder about dark matter and dark energy, and the very nature of reality itself.

We survived our first group of mysteries, so now we move onto our second set of stuff of amazing Milky Way mysteries. How many spiral arms does our galaxy have, and why does everything keep dying every 60 million years or so?

Apparently this is at least a 2 part series. This week we continue examining some of the baffling mysteries of the Solar System, where we fill your head with more questions than answers. Sometimes we've just got to share the enjoyment of not knowing the a

We know a lot about our Solar System, but there's an awful lot that's a complete and total mystery. Today we're going to begin a series of unknown length examining some of these mysteries, and explain the best theories astronomers have so far.

Last week we talked about Herschel the people – William Herschel, his sister Caroline, and his son John. This week we look at the Herschel Space Observatory, a mission launched in 2009 to reveal the coldest and dustiest regions in the Universe.

Ancient astronomers knew of 5 planets, Mercury, Venus, Mars, Jupiter and Saturn - 6 if you count Earth. But then in 1781, William Herschel discovered an entirely new planet, boosting the number of planets to 7. Let's learn about Herschel, his equipment, h

Even in ancient times, astronomers realized there was something different about the planets - they move! The movement of the planets and their moons are governed by gravity. And as we all know, gravity can do some funny things.

This is going to be one of those weeks where we tackle something you're mentally avoiding. You know all those astronomical terms, like alt-azimuth, right ascension and declination, arc seconds and arc minutes? Of course not, your mind has blocked them out

Last week we talked about Fermi the man, now we're going to talk about Fermi the space telescope. That's right, Enrico Fermi made such an impact in the astronomy and physics community that he got a space telescope named after him. Let's take a look at wha

Today's episode of Astronomy Cast is about another famous physicist: Enrico Fermi. We've already taken a look at one of Fermi's most famous ideas, the Fermi Paradox - or, where are all the aliens? But let's meet the man behind the ideas, the namesake for

Let's assume that humans survive the next few hundred years without destroying ourselves, or the planet, and we actually become a space faring civilization. What kinds of challenges will we face, and what projects will we build to expand ourselves out int

What if our universe was just one in an infinite number of parallel universes; a possible outcome from the specific predictions of quantum mechanics. The idea of multiple universes is common in science fiction, but is there any actual science to back this

You know how a police siren changes sound when it passes by you? That's the doppler effect. It works for sound waves and it works for light waves. Astronomers use the doppler effect to study the motion of objects across the Universe, from nearby extrasola

We've talked about the biggest of the big, now let's focus in on the smallest of the small. Let's see what's inside that basic building block of matter: the atom. You probably know the basics, but with ever more powerful particle accelerators, physicists

When the Sun's solar winds crash into the Earth's magnetosphere, we get to enjoy an incredible light show called auroras, or the Northern and Southern Lights. Let's learn about what causes these incredible phenomena, and the best times and places that you

You might know the name "Hubble" because of the Hubble Space Telescope. But this phenomenal observatory was named after one of the most influential astronomers in modern history. Hubble discovered that galaxies are speeding away from us in all directions,

Launching a rocket into space requires a big effort on the ground. Space agencies have built up huge infrastructures to store, prepare and launch rockets. Let's take a look at what's involved on the ground at a place like Cape Canaveral. What happens befo

Every now and then, the Moon destroys the Sun. Okay, not destroys, covers. Well, not really covers, but from here on Earth, sitting inside the shadow of the Moon, that's what it sure looks like. These events are called eclipses, or more precisely, transit

Astronomers have been searching for the mysterious Planet X for hundreds of years. It was the search for a theoretical planet beyond Uranus that turned up Neptune, and then again for Pluto. And even now there are some astronomers who think there's a more

Imagine an object with the mass of the Sun, crushed down to the size of Manhattan. Now set that object spinning hundreds of times a second, blasting out powerful beams of radiation like a lighthouse. That's a pulsar, one of the most exotic objects in the

This week we're going to talk about famous stars. But not those boring human ones you read about in People magazine. No, we're talking about those hot balls of plasma across the distant Universe. The close ones, the bright ones, the massive ones, the gian

We think we live near an average star, but that's not the case at all. Compared to most stars in the Universe, the Sun is a giant! Let's look at the small end of the stellar spectrum, to stars with a fraction of the size and mass of our own Sun. There are

This week we step away from our regular programming to bring you a live show from Dragon*Con in Atlanta. Pamela shares the stage with SETI researcher Seth Shostak. Together they discuss the technology and science of searching for intelligence, And answer

If you live in a city, it's possible that you've never seen the Milky Way with your own eyes. To really appreciate everything the night skies have to offer, you've got to get out of the city, away from the lights, where the skies are really dark. But thos

Did you know that our Solar System is a rarity with its single star. Astronomers believe that most star systems out there actually contain 2 or more stars – imagine seeing a sky with 4 suns. These binary and multiple star systems are a great target for

Take a quick breath. There, that's what we're going to talk about today – the atmosphere. And not just the Earth's familiar atmosphere, but the strange, exotic and deadly atmospheres we find in the Solar System and surrounding extrasolar planets.

We've explained how to get into astronomy and buy your first telescope. Now we're going to take things to the next level and get you drooling about bigger and better telescopes. If you're serious about astronomy, what kinds of telescopes will give you the

It's been more than 40 years since humans first set foot on the Moon. But plans are in place to return humans to the surface of the Moon, and maybe even to asteroids and the planet Mars. New rockets, landers and flight technology are all under development

Astronomy is one of the scientific fields that have been completely shaken up by new media. The Internet has enabled communication between researchers in a dramatic new way, creating new collaborations, removing obstacles, and drawing in an army of enthus

For those non-scientists trying to get their original ideas accepted by the scientific community, you've got to have thick skin. It might seem like there's a vast conspiracy, or a general attitude that drives away original, but unorthodox ideas. But that'

Have you ever wondered how astronomers do their research? How do they go from idea or question, to gathering their data, to publishing the research. What are all the hoops they have to jump through, the paperwork to fill out, and the cool toys they get to

In science fiction it's easy to hop into your spaceship and blast off for other stars. But the true distances between stars, and the limits of relativity make interstellar travel almost impossible with our current technology. What would it really take to

What will we eventually be able to see on extrasolar planets? What does an infinite Universe mean? And what's down there, inside a black hole? If you've got a question for the Astronomy Cast team, please email it in to info@astronomycast.com and we'll try

If you want to travel into the Solar System, you have to get off the Earth. Traditionally, that meant blasting off in a rocket. But there's another strategy for escaping the Earth's gravity. Climb to the top of an extremely tall tower, and just jump away.

Why was there a difference between the amount of matter and antimatter at the beginning of the Universe? Mathematics lets us travel faster than light speed, so why can't we? And are there stars forming around black holes? If you've got a question for the

We know there's life in the Universe. We see it all around us here on Earth. But is there life anywhere else? By studying the extremes that life can take here on Earth, scientists are learning just how hardy and adaptable life can really be. And if you co

Why are black holes black? Can a huge mass of humanity make the Earth wobble? And what's so bad about space pollution anyway? If you've got a question for the Astronomy Cast team, please email it in to info@astronomycast.com and we'll try to tackle it for

The surface of the Earth feels solid under your feet, but you're actually standing on a plate of the Earth's crust. And that plate is slowly shifting across the surface of the Earth. Over geologic timescales, plate tectonics has totally resurfaced our pla

Will robots be able to avoid the heat death of the Universe? Can galaxies orbit each other like binary stars? And what are the dangers of space radiation to astronauts on the Moon? If you've got a question for the Astronomy Cast team, please email it in t

You're familiar with volcanoes, eruptive vents where hot magma escapes the Earth's interior – sometimes with disastrous effects. But did you know that volcanoes have shaped many of the planets and moons in the Solar System, not just our own Earth? And j

Questions Show: Galileoscope, Black Hole Time, and What Exactly is Energy?

How can you get a Galileoscope of your very own? What happens to time inside a black hole? And what exactly is energy anyway? If you've got a question for the Astronomy Cast team, please email it in to info@astronomycast.com and we'll try to tackle it for

One of the most amazing aspects of quantum mechanics is quantum entanglement. This is the strange behavior where particles can become entangled, so they're somehow connected to one another – no matter the distance between them. Interact with one particl

What starting telescope equipment does the Astronomy Cast team suggest? How much energy does a black hole generate? And how do we measure time outside the Earth? If you've got a question for the Astronomy Cast team, please email it in to info@astronomycas

Last week we took a peek into the tiny world of quantum mechanics, and its unintuitive, but very accurate mathematical predictions. And although we all appreciate the physics lesson, you're probably wondering what this all has to do with astronomy. Well,

What would happen if the Moon wasn't tidally locked to the Earth? What happens to all that mass and energy disappearing into a black hole? And how can we explain the space station's crazy orbit? If you've got a question for the Astronomy Cast team, please

Quantum mechanics is the study of the very tiny; the nature of reality at the smallest scale. It's a science that defies common sense, and delivers no helpful analogies. And yet it delivers the goods, making scientific predictions with incredible accuracy

Are new stars dark until their photons reach the surface? How fast do neutrinos travel? And what’s the story with Hawking Radiation? If you've got a question for the Astronomy Cast team, please email it in to info@astronomycast.com and we'll try to tack

This week we’re going to think big. Bigger than big. We’re going to consider the biggest things in the Universe. If you could pull way back, and examine regions of space billions of light-years across, what would you see? How is the Universe arranged

Questions Show: The Source of Atmospheres, the Vanishing Moon, and a Glow After Sunset

How do planets get their atmospheres? What would happen to the Earth if the Moon just disappeared? And what’s that strange glow we see after sunset? If you've got a question for the Astronomy Cast team, please email it in to info@astronomycast.com and w

And now we reach the end of our tour through the electromagnetic spectrum. Last stop: gamma rays. These are the most energetic photons in the Universe, boosted up to incredible energies in the most violent places in the Universe. Gamma rays are tricky to

Can our Sun generate a solar flare that would wipe out life on Earth? Has the Large Hadron Collider answered any questions about the Higgs boson? And what would happen if you shined your flashlight out the front window of a spaceship going almost the spee

If you've ever broken a bone, X-rays are a part of the electromagnetic spectrum. Doctors use X-rays to study the human body, and astronomers use X-rays to study some of the hottest places in the Universe. So let's put on our X-ray specs, and see what we c

Pamela was lucky enough to attend the NorthEast Astronomy Forum, and while she was there she held a live questions show. And now you get to join in an hear the interesting questions, and Pamela's interesting answers. If you've got a question for the Astro

Our next visit in this tour through the electromagnetic spectrum is the ultraviolet. You can't see it, but anyone who's spent a day out in the hot sun without sunblock has sure experienced its effects. Ultraviolet radiation is associated with the birth of

Optical astronomy; now this is the kind of astronomy a human being was born to do. In fact, until the last century, this was the only kind of astronomy anybody ever did. Now we've got the whole electromagnetic spectrum to explore, but our heart still belo

If there was enough mass to cause a big crunch, would inflation go backwards too? How do spacecraft know that hydrogen is bonded to water? And why can't we see everything that's ever fallen into a black hole? If you've got a question for the Astronomy Cas

Today we continue our unofficial tour through the electromagnetic spectrum, stopping at the infrared spectrum - you feel it as heat. This section of the spectrum gives us our only clear view through dusty material to see newly forming planetary systems an

Last week we examined the largest wavelength in the electromagnetic spectrum: radio. This week we get a little smaller… but not too small! And look at the next step in the spectrum, the submillimeter. Astronomers have only recently began exploiting this

This week we wonder if you can made a black hole by accelerating a mass, but then can you un-make it again? Will the Earth ever be tidally locked to the Sun? And can dark matter crush an unsuspecting space ship? If you've got a question for the Astronomy

Astronomers are very resourceful, when it comes to light, they use the whole spectrum - from radio to gamma rays. We see in visible light, but that's just a tiny portion of the spectrum. Today we're going to celebrate the other end of the spectrum; the ra

Questions Show: Multiple Big Bangs, Satellite Collisions and the Size of the Universe

This week we wonder if the Universe is going to collapse and then expand again, how satellites can have such different velocities, and the size of the observable Universe. If you've got a question for the Astronomy Cast team, please email it in to info@as

When it comes to telescopes, bigger is better. But bigger is more expensive. Way more expensive. To keep the costs reasonable while improving the sensitivity of their instruments, astronomers use an amazing technique called interferometry. Instead of buil

Questions Show: Shooting Lasers at the Moon and Losing Contact with Rovers

This week we find out how hard it is to hit the Moon with a laser, and if scientists lose contact with the Mars rovers when they go behind the Sun. If you've got a question for the Astronomy Cast team, please email it in to info@astronomycast.com and we'l

You can't make a Solar System without a whole lot of dust. And that's the problem. This dust has blocked astronomers views into some of the most fascinating parts of the cosmos. It shields the galactic core, enshrouds newly forming stars and their planets

You’ve heard us talk about capsules, you’ve heard us talk about space suits, well today we take a look at the only currently in use reusable space craft. It’s a not a bird, its not a plane – It’s the US Space Shuttle. And to make it interesting

Orbiting black holes generate gravity waves. This week Bob Novella of Skeptics Guide to the Universe is going to pepper Pamela with questions, testing her ability to leap from tides to gravitational waves to Higgs bosons. We'll see where this takes us on

Dreaming up new planets is a favorite pastime of science fiction writers, but the universe often has them beat – coming with planets in place and forms that we had quite thought to imagine. Today we know of 228 stars orbiting alien stars, and in this ep

Questions Show: Moons and the Drake Equation, Stars in the Void, and Rings Around Stars

This week we find out if moons around other planets could support life, if there's anything out there between galaxies, and whether stars form rings. If you've got a question for the Astronomy Cast team, please email it in to info@astronomycast.com and we

The space capsule has been around for almost 50 years, when Yuri Gagarin headed to space in 1961. There have been many programs that used capsules by both the Americans and the Russians, and even the Chinese are using them now for their spaceflight progra

As astronomers discovered that we live in a great big universe, they considered a fundamental question: is the universe the same everywhere? Imagine if gravity was stronger billions of light years away… Or in the past. It sounds like a simple question,

We did a wildly popular three part series about the center, size and shape of the Universe. But every good trilogy needs a 4th episode. This week we look at age of the Universe. How old is the Universe, and how do we know? And how has this number changed

This week we find out when stars get torn apart from gravity, how we can see supermassive black holes, how liquid water could have existed on Mars in the past, and much more. If you've got a question for the Astronomy Cast team, please email it in to info

As we've mentioned before, the Universe is trying to kill you. And for astronauts, that's truer than ever. One step out into the vacuum of space would be a world of hurt for an unprotected astronaut: the freezing cold temperature, the lack of atmospheric

With Christmas just around the corner, we thought we'd investigate a mystery that has puzzled historians for hundreds of years. In the bible, the birth of Jesus was announced by a bright star in the sky that led the three wise men to his birthplace. What

This week we find out the difference between an astronomer, an astrophysicist, and a cosmologist, the search for the stars that shared our nebula, hidden objects in Lagrange points, and much more. If you've got a question for the Astronomy Cast team, plea

Space is totally inhospitable. If the freezing temperatures don't get you, the intense radiation will kill you. Or the vacuum, or the lack of breathable atmosphere, or meteoroid impacts. Well… you get the idea. That's why most space exploration is done

This week we find out the distance between Betelgeuse and Bellatrex, how astronomers measure distance between objects, the possibility that an object could mess up the orbit of Earth, and the reason for different sizes of stars.

In the old days, astronomers had to beg for telescope time. They'd put together a proposal, convince observatories to gather data for them, crunch that data and release the results. No telescope, no results. But everything's different now. Fleets of robot

Today, time rules our lives. We live each day with the moments broken up into hours, minutes and seconds. We never seem to have enough time. But can you imagine not being able to tell time at all, where the movements of the Sun and the stars was the only

As part of her trip to England, Pamela had a chance to sit down with Oxford astrophysicist Chris Lintott and record an episode of Astronomy Cast. From the first stars to the newest planets, molecules and the chemistry that allows them to form affects all

It's time for a third lunar chapter. We've talked about the physical characteristics of the Moon, and the exploration. Now we're going to talk about the plans to return to the Moon. From the upcoming lunar reconnaissance orbiter to the plans to have human

This week we explore galactic spiral arms, seismic quakes on the Sun, and our picks for astronomy gear. If you've got a question for the Astronomy Cast team, please email it in to info@astronomycast.com and we'll try to tackle it for a future show. Please

Let's continue on our journey to the Moon. Last week we talked about the physical characteristics of the Moon, its appearance in the sky and how it interacts with the Earth. This week we're going to take a look at how scientists have expanded our understa

Questions Show: Ice in Space, Expansion of the Universe, and Death from the Skies

Another week, another batch of questions. If ice disappears in your freezer, how can it last in space? How can the Universe be expanding faster than the speed of light? And what is the risk from a coronal mass ejection in an airplane? All this and even mo

Hey, here's a topic we haven't gotten around to yet... the Moon. Today we look at our closest astronomical companion: the Moon. What impact does the moon have on our lives, where did it come from, who walked on it, and are we ever going to walk on it agai

We're back to a themeless questions show. We're right across the Universe this time. Why are the planets lined up in a nice flat plane? Why are there no green stars? And is the Oort Cloud contaminating our understanding of the cosmic microwave background

We say it all the time here on Astronomy Cast: the Universe is trying to kill us. This week, Pamela is joined by Dr. Phil Plait to discuss his new book, Death from the Skies. Phil and Pamela talk about asteroid strikes, solar flares and gamma ray bursts.

Everyone loves a theme. And this week we've collected together some of your questions about relativity. More light speed spacecraft, twin paradoxes, and the mixing up of gravity, time and mass. If you've got a question for the Astronomy Cast team, please

When you think about the best pictures in astronomy, almost every one is a nebula; the pillars of creation in the Eagle Nebula, or the complex Helix Nebula - or my personal favorite, the Ring Nebula. They're beautiful, wispy clouds of gas and dust that si

Questions Show: Galactic Dust, the Speed of Photons, and the Big Bang Calculations

Another week, another roundup of your questions. This week listeners asked: what is galactic dust anyway, and where does it come from? Why can photons move at the speed of light? And how can astronomers know what happened right after the Big Bang? And the

You know what this show needs? More aliens. Since we don't seem to have any visiting right now, we're going to have to find some. SETI is an acronym. It stands for the Search for Extraterrestrial Intelligence. But there's more to SETI than just putting up

Questions Show - Alignment with the Galactic Plane, Destruction from Venus, and the Death of the Solar System

Another week, another roundup of your questions. This week listeners asked: are we all going to die in 2012 when the solar system passes through the galactic plane? Did Venus make the Moon? And what will extraterrestrials see when the Sun is dead and gone